Quaternary ammonium derivatives of vinylpyridine-polyinylbenzene copolymers



Patented m; c.1951

2,540,985 qua-mama]! AMMONIUM nnluva'nvs or mn-ronrvmnnslvznivs coronmas Elwood F. Jackson, Ludlow, Mam, aaai nor to Monsanto Chemical Company, St. Louis, Mo" a corporation of Delaware Application December 8, 1949, Serial N0. 131,507

7 Clallnl. (Cl. 260-881) This invention relates to quaternary ammonium derivatives of copolymers oi vinyl pyridine and divinyl benzene or trivinyl benzene and to processes for preparing them.

Thecopolymers of vinyl pyridine and divinyl 5 with sodium hydroxide converted the quaternary benzene or trivinyl benzene are disclosed and salt into aquaternary base. claimed in my copending application 5. N. 55,425 Example "I filed October 19, 1948. These copolymers are insoluble and iniusible resins which are particu- A bead resin made by the aqueous'suspension larly useful as ion exchange media. However. polymerization of 100 parts of vinyl pyridine with for the removal of some ions and especially for parts of divinyl benzene was slurried in the breakdown oi salts such as sodium chloride methanol. The slurry was cooled to about 0 C. the copolymer resins were ineflicient and of little and methyl bromide which had been precooled object of this invention is to provide 15 azft ati n 'fihz rfiiu t c i f lfi l lgl quaternary derivatives of copolymers of vinyl mide added was in excess of a molar equivalent pyridine and the divinyl benzene or trivinyl amount based on the copolymer. The slurry was benzene, maintained at 0 C. for about two hours with A further object is to provide new ion exchange constant agitation and then the temperature was r n raised to about 35 C. The reaction was con- These and other objects are attained by retinued at 35" C. for about eighteen hours with acting a copolymer of vinyl pyridine and divinyl constant agitation. The methanol and excess benzene or trivinyl benzene with a quaternizing methyl bromide were removed by filtration and agent, in tr the beads were washed with methanol to remove The following examples are given illus aresidual traces of the methyl bromide. The tion and are not intended as limitations on the quaternary ammonium salt thus produced was scope of this invention. Where parts are menin the same physical form as the unmodified cotioned they are parts by weight. polymer. It was insoluble and infusible, hard Example I and tough. The salt could be converted to the One mol of a copolymer prepared by polymerizg gm gffig I2 3, fif gg -fiff it with ing a mixture of 100 parts of vinyl pyridine and 5 parts of divinyl benzene, was slurried in methanol. Example IV 1.5 mols of methyl iodide were added to the slurry which was then agitated for about twelve A bead. m was prepared by copoly o merizing 100 parts of vinyl pyridine with 5 parts hours at about 30 C. Excess methyl iodide and of mvmyl benzene in aqueous emulsion The methanol were removed by filtration. The prodbeads were insoluble and intusible. One mol of not was a quaternary salt having a methyl group the beads was slurried in dioxane and about 1.2 and an iodme atom attached to the nitrogen of mols of diethyl sulfate were added. The slurry the pyridine ring. The quaternary salt could be 40 was heated at reflux temperature for three hours converted to a quaternary ammonium hydroxide by slurrying the resin in an aqueous medium containing sufilcient sodium hydroxide to react with the iodine and form sodium iodide. Since the resin was insoluble in water, it could easily be recovered as the quaternary base by simpl filtration.

Example II A slurry was prepared by dispersing 1 mol of a vinyl pyridine-trivinyl benzene copolymer in benzene with agitation. Said copolymer was prepared by polymerizing 100 parts of 2-vinyl pyridine with 11 parts of trivinyl benzene. About 1.5 mols of methyl iodide were added to the slurry which was then placed in a sealed container which was maintained at about 50 C. for about fifteen hours under constant agitation. The containerwas then opened'and the quaternized resin was recovered by filtration. Further treatment with constant agitation. Thereaction medium was then cooled and filtered to recover the in soluble quaternary salt. The salt was easily converted to the hydroxide by reacting it with sodium hydroxid in an aqueous slurry.

The copolymers which are the starting materials or this invention are copolymers of parts of vinyl pyridine with from 1 to 20 parts of divinyl benzene or trivinyl benzene. They may be prepared by mass, solution, suspension or emulsion polymerization methods as more fully set forth in my copending application S. N. 55,425. They are insoluble and lnfusible resins, some 01' which contain a slight amount of red or yellow coloring which appears to be due to the internal structure or the resin, since the color cannot be leached out. A majority of the copolymers are substantially colorless and transparent. They range from soft elastic materials to hard rigid materials and are substantially insoluble in acids, alkalies, water and organic solvents. However the copolymers swell in aqueous media and become permeable to reactants such as the quaternizing agents so that practically complete reaction may be obtained in spite of the insolubility.

The quaternizing agents should be used in at least molar equivalent quantities based on the copolymer, although it is preferred to use an excess in order to speed up the reaction and to ensure a complete reaction. Due to the insoluble nature of the copolymer and the quaternary derivatives thereof, the excess quaternizing agent may be easily removed from the finished product by'flltration and washing.

The insoluble nature of the copolymers makes.

it necessary to prolong the quaternizing' action in order to ensure complete reaction. The quaternizing reaction is best carried out in a slurry of particulate copolymer in an inert organic material such as benzene, methanol, dioxane, ethanol, isopropanol, butanol, Cellosolve, Carbitol, ethyl lactate, ketones, nitroparafiins, etc. These materials are not solvents for the polymer but do dissolve the quaternizing agent and make it possible for the latter to penetrate the porous copolymer particles.

Among the quaternizing agents which may be used are the alkyl halides such as methyl bromide, ethyl'bromide, methyl iodide, ethyl iodide, butyl iodide, lauryl iodide, etc., alkyl sulfates such as the diethyl, dimethyl, dipropyl, dibutyl, diisobutyl, dioctyl, dilauryl etc., sulfates, alkyl aryl sulfonates such as butyl benzene sulfonate, butyl toluene sulfonate, ethyl toluene sulfonate, octyl benzene sulfonate etc.

The quaternary salts of this invention may be used in the dyestufi industry as intermediates but a more important use is in the form of the free base as ion exchange media. By treating the salts with an alkali such as ammonium, sodium, potassium, rubidium or cesium hydroxide in an aqueous slurry, the salt forming group is replaced by the hydroxyl group. Again the insoluble nature of the compounds makes the process for removing the salt formed with the alkali a matter of simple filtration and washing. The

quaternary ammonium hydroxides thus formed are strong bases which will not only remove anionsw from the weakest of acids but also will split salts such as sodium chloride, removing the chlorine ions from the salt solution and producing sodium hydroxide:

Dynamic evaluations of the quaternary bases prepared as shown in the examples gave values of between 25 and kilograins per cubic foot of resin, calculated as calcium carbonate when acids of varying strengths were used. The tests also disclosed that the resins had a capacity of greater than 12 kilograms per cubic foot when 4 used to remove the anion from sodium chloride. The dynamic evaluation test involves using the resins in a standard columnar ion exchange apparatus under conditions closely approximating standard operating conditions.

The quaternary ammonium bases of this invention are insoluble, infusible and relatively hard when compared to more conventional ion exchange resins. They contain no toxic or colored impurities which can be leached out by the media being treated in ion exchange processes. They may be regenerated by treatment with strong alkalies. Since they are insoluble in acids, bases and organic solvents. they may be used to remove anions from aqueous and organic media without danger of softening the resin and plugging up the ion exchange apparatus. Being infusible, they may be used in'ion exchange operations at temperatures considerably above that normally used'thus providing a method for purifying various materials which are solid at room temperature but liquid at temperatures between 50 and C.

It is obvious that many variations may be made in the products and processes of this invention without departing from the spirit and scope thereof as defined in the appended claims.

What is claimed is:

1. A quaternary ammonium salt of a copolymer of 100 parts of vinyl pyridine and from 1 to 20 parts of a compound taken from the group consisting of divinyl benzene and trivinyl benzene.

2. A quaternary ammonium salt of a copolymer of 100 parts of vinyl pyridine with from 1 to 20 parts of divinyl benzene.

3. A quaternary ammonium salt of a copolymer of 100 parts of vinyl pyridine and from I. to 20 parts of trivinyl benzene.

4. A quaternary ammonium hydroxide of a copolymyer of 100 parts of vinyl pyridine and from 1 to 20 parts'of a compound taken from the group consisting of divinyl benzene and trivinyl benzene.

5. A quaternary ammonium hydroxide of a copolymer of 100 parts of vinyl pyridine and from 1 to 20 parts of divinyl benzene.

6. A quaternary ammonium hydroxide of a copolymer of 100 parts of vinyl pyridine with from 1 to 20 parts of trivinylbenzene.

'l. A compound taken from the group consisting 01' quaternary ammonium salts and quaternary ammonium hydroxides of copolymers of 100 parts of vinyl pyridine and from 1 to 20 parts of a compound taken from the group consisting of divinyl benzene and trivinyl benzene.

ELWOOD F. JACKSON.

REFERENCES crrEn The following references. are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,484,420, Minsk Oct. 11, 1949 

7. A COMPOUND TAKEN FROM THE GROUP CONSISTING OF QUATERNARY AMMONIUM SALTS AND QUATERNARY AMMONIUM HYDROXIDES OF COPOLYMERS OF 100 PARTS OF VINYL PYRIDINE AND FROM 1 TO 20 PARTS OF A COMPOUND TAKEN FROM THE GROUP CONSISTING OF DIVINYL BENZENE AND TRIVINYL BENZENE. 